Key Financial Data Of Group
| Concept | As at 2023-09-30 | 2023-07-01 to 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-09-30 | 2022-07-01 to 2022-09-30 | 2022-04-01 to 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | — | — | 
                                                5,328,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,282,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | 
                                                -199,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                311,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -33,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | — | 
                                                -117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                199,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                22,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | — | 
                                                54,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                271,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                4,955,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,952,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,677,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | 
                                                11,858,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,085,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,776,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | 
                                                -14.71
                                                
                                             | 
                                                -36.19
                                                
                                             | — | 
                                                61.31
                                                
                                             | — | 
                                                6.04
                                                
                                             | 
                                                7.05
                                                
                                             | 
| Diluted earnings per share | — | — |  | — |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.3810
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.3473
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.3630
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                75,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -81,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -158,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -67,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -254,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | 
                                                43,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                263,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                234,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                320,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                269,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |